Truncated dome insert pins with flexible Mylar Layout Grid

ABSTRACT

A plastic device, in the shape of a truncated dome, affixed to a pedestrian sidewalk, crosswalk or platform by use of a flexible Mylar layout grid and a drilled and glued insert location , placed to provide a tactile and visual alert to disabled persons as to the location and edge of a platform or walkway, where the sidewalk or walkway transitions to a roadway or elevation change. The device consist of a molded plastic “truncated dome”, with an integrally molded stem and a pre drilled Mylar mat positioning guide to ensure the truncated domes are installed with in the guidelines of the American&#39;s with Disabilities Act. The truncated domes will provide the correct tactile alignment, slip resistant surface, as well as the correct contrast in color between the truncated domes and substrate as required in the American&#39;s with Disabilities Act.

BACKGROUND OF THE INVENTION

1. Field of the invention

The American's With Disabilities Act, Chapter Seven, Communication Elements and Features, sections 705.1.1, 705.1.2 and 705.1.3 clearly define the truncated dome size, dome spacing and contrast requirements for the design and installation of a tactile and visual warning system to aid visually impaired individuals in the location of edge of pavement/sidewalk transitions. Section 705.2 defines the surface section and location(s) where the tactile warning system is to be installed. This invention provides for the correct truncated dome size, spacing and contrast requirements of the Act as well as providing for an accurate means of locating the truncated domes as prescribed.

2. Prior Art

Prior inventions consist of the use of pre-cast tiles or panels, rubber sheets with the truncated domes integrally cast within the tile material, and cast concrete pins inserted into bored holes in the existing concrete substrate. The tiles, as disclosed in U.S. Pat. Nos. 4,715,743 and 5,302,049, mats, and cast concrete pins, as disclosed in U.S. Pat. No. 6,971,818, are of one color which does not meet the requirements for the contrast between the truncated domes and the underlying substrate. The aforementioned devices also do not address the slip resistance required for pedestrian safety. The American's With Disabilities Act requires that all public use structures be retrofitted with the required tactile surface (buildings built since the year 2001) and all new public use construction from the year 2001 forward must use the tactile warning surface as an aid to the visually impaired person. The tiles, mats and concrete pins currently available, make the retro-fit process extremely costly and time consuming, and still do not meet all of the requirements of the Act.

Currently, the available alternative to the tiles, mats and concrete pins, is a process using resinous materials that are cast in place over an existing substrate, or the stamping of freshly placed concrete, as disclosed in U.S. Pat. Nos. 5,271,690 and 5,320,790.

This process is also time consuming and costly and does not guaranty adhesion of the resinous domed structures to the underlying substrate nor the correct size and placement of the domed structures as required by the Act. The concrete truncated domes, either formed in panels or mats, or the concrete insert pins, or stamped in fresh concrete, are all subject to cracking and spalling, requiring their replacement.

At this time, the installation of the tiles and mats in existing sidewalks, requires the sawcutting and removal of an area of the existing concrete, re-pouring the concrete to a lower level, to accommodate the thickness of the tiles or mats, and then the installation of the tiles or mats in the newly poured concrete. This is labor intensive and requires the use of equipment not normally carried in a contractor's tool inventory. This method also requires a long period of time and would cause the sidewalk, etc. to be closed to pedestrian traffic while construction is in progress.

The methods and devices, as disclosed in U.S. Pat. No. 6,971,818, are also time consuming and require the use of a special “tool frame” that is currently not commercially available. Reference is made to the use of a template, but the construction of and materials for the template are not defined. The repetitive boring of the concrete substrate, with the use of the tool frame and wet concrete boring machine, is also time consuming and requires tools not normally in a contractor's tool inventory.

BRIEF SUMMARY OF THE INVENTION

It is the object of this invention to provide contractors with a less costly and more efficient means to install the tactile surface required in less time and with the retro-fit ability to install the tactile surface at existing structures. This invention provides to the contractor a means to accurately locate the truncated domes, with the flexible Mylar layout grid, and an ease and speed of installation that requires the least amount of time and the use of tools and manpower already in their inventory. The truncated dome pieces can be installed with the use of a hammer drill (for masonry based substrates) or standard drill motor for wood substrates. The truncated dome insert pins are made of plastic making the size, shape and color easily repeatable and uniform. This also allows for the top of the truncated dome structure to be made into a slip resistant texture as molded into the plastic itself and molded in a high visibility color. The flexible mylar or acetate layout grid, or template, is designed in such a way as to take into account the unavoidable and inevitable variances in the concrete substrate, and still maintain the correct dome to dome spacing as required in the Americans with Disabilities Act. The use of this invention also allows for the replacement of one single truncated dome, should it become broken or missing, instead of the need to replace a complete tile piece. This invention also allows for the correct contrast, as required by the Act, between the plastic truncated dome and the underlying substrate.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE INVENTION

Figure one is a side view of the invention. The bottom dimension of the truncated dome disk is 30 mm in diameter with the top of the disk being 18 mm in diameter, with an abrasive texture molded into the 18 mm surface. The thickness of the disk is 5.1 mm. The disk is molded into one piece with the 5 mm stem molded into the center line of the 30 mm disk for a length of 50 mm. The overall height of the truncated dome insert pin is 55.1 mm.

Figure two depicts the Mylar layout grid from an overhead perspective. Each truncated dome location is 50 mm apart in either the X or Y axis. The first row of truncated domes on the X axis begins 15 mm from the edge of the template. The first row of the truncated domes on the Y axis begins 25 mm from the edge. This allows multiple templates being butted together on either the X or Y axis allowing the correct spacing to be continued for longer applications.

Figure three depicts the truncated dome insert pins installed in a typical 4′ concrete sidewalk substrate. The domes are spaced 50 mm center to center with a 20 mm open area between dome edges. The dome stems are inserted 50 mm into the concrete substrate with the truncated dome disks being 5.1 mm above the surface of the concrete.

Figure four depicts the preferred installation technique for placing the truncated domes into a curb ramp area for the correct tactile transition from a sidewalk to a pavement area. The box layout is preferred as it allows for the wheels of a wheel chair to easily transition the ramp without having to transverse the truncated dome, dome surfaces. The wheels easily pass between the dome surfaces in the 20 mm open spaces.

Figure five depicts the preferred truncated dome layout for a sidewalk to pavement transition or the transition from a platform to railcar. The truncated domes area arranged in a square layout allowing for the smooth transition of wheelchairs across the tactile surface.

DETAILED DESCRIPTION OF THE INVENTION

The flexible Mylar Layout Grid is made of one piece of transparent Mylar 12000 mm in length by 630 mm in width. The truncated dome locations begin 15 mm from the edge of the Mylar, on the X axis, and begin 25 mm from the edge of the Mylar on the Y axis. The truncated domes are spaced 50 mm apart, on each of the X and Y axis allowing for 20 mm of open space between each of the 30 mm dome disks. The Flexible Mylar Layout Grid allows for the minor imperfections in the surface of the substrate allowing for correct spacing of the domes to be maintained per The Americans With Disabilities Act requirements. The layout grid is pre-marked and drilled to allow the correct positioning and marking of the substrate. The Mylar Layout Grid is flexible from −100 degrees F. to +300 degrees F. and is resistant to oils, greases, water and aromatics. It normally does not become brittle or yellow with age. The Truncated Dome Insert Pins are made of a one piece, injection molded, polycarbonate plastic, in a high visibility color such as orange, red or blue. The insert pins are protected from ambient ultraviolet solar radiation and will not distort in size in a normal application heat range. Polycarbonate plastic is heat resistant, tough, and shatter resistant. Each Truncated Dome Insert Pin is 55.1 mm in total length, has a dome with a 30 mm base and an 18 mm top with a slip resistant surface molded into it during fabrication, and a 5 mm stem, or insert piece, molded into it along the centerline of the X axis, for a 50 mm length. The thickness of the truncated dome section is 5.1 mm. By making the insert pins of plastic, on an injection molding machine, each piece is exactly the same size, and is interchangeable with any other piece.

The devices are installed to make the detectable warning surface by 1.) cleaning the substrate that they are to be installed on. 2.) Laying the Flexible Mylar Layout Grid onto the substrate and aligning it correctly with the X and Y axis. 3.) The layout grid is then affixed to the substrate by drilling the pin locations on the four corners and anchoring in place with masonry screws and washers. 4.) The remaining pin locations are then marked onto the substrate with an indelible marker or paint. 5.) The Mylar Layout Grid is then removed from the substrate by removing the masonry screws and laying the layout grid aside. 6.) The points marked with the indelible marker are then drilled out with a 6 mm bit affixed to a standard hammer drill, to a depth of 55 mm. 7.) After drilling the locator holes, the holes are vacuumed with the aid of a shop vacuum to remove drilling spoils. 8.) A small quantity of adhesive is then inserted into the 6 mm drill hole. 9.) The polycarbonate insert pins are then inserted into the 6 mm pre-drilled and glued holes, seating the 30 mm base to the substrate. 10.) Installation is now complete. 

1.) The flexible mylar layout grid allows for the correct placement of the truncated dome insert pins on an existing substrate allowing for the inevitable flexion and tension of the concrete surface finish. The Mylar layout grid is pre-marked and drilled and is transparent. The layout grid can either be butted together or overlaid, for longer applications, such as a subway platform or longer sidewalk to pavement transition, and still maintain the correct center to center spacing of the insert pins as referenced by The Americans With Disabilities Act. A Carpenter will be able to use the layout grid without extensive additional training or laborer personnel could be trained to do the installation in a short period of time. Layout and installation can be accomplished with tools and personnel already in a contractors standard inventory. This layout and installation system does not interfere with normal business activities and does not require the closing of sidewalks and entrances for a long period of time. Sections as small as four feet can be closed and installed in as little as 2 man hours. 2.) The polycarbonate insert pins are injection molded and have an integral anti-slip surface molded into the 18 mm top surface. The plastic is stabilized against normal ultraviolet solar radiation and are molded in a high visibility color, such as red, orange or blue. The size and shape, as well as the contrast between the insert pins and underlying substrate, conform to the requirements as stated in the Americans with Disabilities Act. 3.) The insert pins are all of the same shape and size and are interchangeable with each other. The standard size allows for replacement of an individual pin should one become broken or missing due to maintenance or snow removal operations. This is far preferable than having to remove a complete pre-molded clay tile to replace one broken truncated dome surface. No concrete needs to be removed for the placement of the plastic truncated dome insert pins. Should one become missing, the contractor needs only to re-drill the existing location point, by drilling out the remaining stem piece, and then glue in a new truncated dome insert pin. 4.) Installation may be accomplished using tools already in the contractor's inventory and with minimal additional training of existing skilled or semi-skilled personnel. No rental or specialty tools or equipment are required for normal installation. No special tool platforms or machine jigs are required. Installation in new concrete can be performed by using the layout grid during the finishing process and inserting the pins into the pre-marked hole locations in the fresh concrete. 5.) The high visibility color and high contrast with the underlying substrate, allow the limited sighted individual to easily distinguish between sidewalk and pavement areas. The 20 mm spacing between dome structures allows for wheelchair wheels to easily negotiate the tactile warning strip without having to roll over the dome structures. The integrally molded anti-slip surface provides a traction area when rain or snow is present. 